feat: support function params + stack based compiler!

example.rx

@@ -1,15 +1,18 @@
 extern putchar
 
-fn main() {
+fn hello() {
     local h = 72
     local e = 69
     local l = 76
     local o = 79
-    local nl = 10
     putchar(h)
     putchar(e)
     putchar(l)
     putchar(l)
     putchar(o)
-    putchar(nl)
+}
+
+fn main() {
+    hello()
+    putchar(10)
 }